Ovulation itself only lasts for more or less 24 hours, but the ovulatory phase (days in which you are fertile) is usually a couple of days before and after ovulation, around 5 to 7 days. Ovulation happens when an egg is released from the ovary and usually happens during the middle of the cycle. The reason why you are fertile for days other than just your ovulation day is because sperm can survive in the mucus for up to 5 days before the egg is released. This means they have a chance to fertilize the egg during the 5 to 7 days.  

These are the organs that are typically thought of as "pathways" from the ovaries to the uterus. Sperm will swim from the opening of the vagina, through the cervix, across the uterus, and then into the Fallopian tubes.  

It is highly impossible if you are healthy and have a normal reproductive environment. However, some people might have ovulation, which is what happens when an egg isn't released during the menstrual cycle, and a menstrual cycle that's too long or too short may hinder ovulation. There are several causes for this, such as PCOS or primary ovarian insufficiency (POI), and it is the primary reason for infertility among women. 

There are several factors affecting ovulation: a woman's age, medication, weight, hormonal imbalances, mental well-being, smoking and alcohol consumption, external and environmental factors, etc.